See, the thing is, you can make ANYTHING work with training.
You can grapple for the outside OR inside, as long as you train that way.
And weapons are an extension of the arm, so they wouldn't change the principles that much.

Assuming it's a self-defense situation and given a choice I'd take the blind spot. I'd pop to the outside, move into the blind spot, and keep on running. If I was good enough that day, I might be able to slip in one counter to prevent the dude from being able to turn and chase me so fast.

But honestly, I don't think you have a choice. What I do has a hell of a lot more to do with how my opponent is standing, what he is doing, and how he has reacted to the stuff I tried so far, than what my personal preferences are.

Also standing in front of your opponent and trading shots isn't my idea of taking the center line, the key word there being "taking". When I take the center line I crash it, and a remove whatever was in the way by forcing it off the line. Doing so not only allows me to control the line, but also the "center" by forcing by opponent back, distrupting his balance, or both.